Multilayer substrate and the manufacturing method thereof

ABSTRACT

A multilayer substrate, comprising a first substrate, a connector and a second substrate, is disclosed. The first substrate has a circuit pattern. The connector, coupling onto the first substrate, has a ring structure, in which a plurality of holes are separated a predetermined distance from one another. The second substrate, coupling onto the second substrate by inserting the connector, has a circuit pattern, which is electrically connected to a circuit pattern formed on the first substrate using the plurality of holes formed on the connector. A multilayer substrate and a method for producing it in accordance with the present invention can shield the EMI generated by a high-speed switching element.

TECHNICAL FIELD AND BACKGROUND OF THE INVENTION

The present invention relates to a substrate and a method for producingit. More specifically, the present invention relates to a multilayersubstrate and a method for producing the multilayer substrate.

Recently, with the accelerated tendency of ubiquitous computing anddigital convergence, semiconductor integrated circuits are beingintegrated enough to perform system functions with a single chip, thesignal processing is speeding up, and less power is needed in order tofit in mobile environments. In these electronic environments, thetechnology to design a circuit to secure the noise margin by loweringthe signal-to-noise ratio is being increasingly important. Besides, asuniversal electronic devices with Wireless communication become morebroadband, to meet the increased amount of data communication and thedemand for high-speed signal processing, products become smaller, andparts are more densely mounted to implement multi-functions, electricalfeatures, such as signal integrity, power integrity, electromagneticinterference and electromagnetic integrity, are becoming very important.

According to conventional art, when printed circuit boards (PCBs) arestacked, the electrical signal between the stacked PCBs was connected ata specific part. That is, a module pin was brought close to an arrangedplate to connect an electrical signal between PCBs. As such, whenlocally connecting a signal, a feedback current on the signal can beformed by a pin, adjacent to the signal line, and an electrode pattern,causing problems, such as deterioration of signal integrity andelectromagnetic interference (EMI), when a high-speed signal isdelivered.

The “stacked processor construction” presented in U.S. Pat. No.6,362,974 discloses only an outline of arrangement and connectionconceptually, not a specific method for connecting a signal line,thereby not being able to solve the problems of signal integrity andEMI, described above.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the presentinvention will become better understood with regard to the followingdescription, appended claims, and accompanying drawings where:

FIG. 1 is a sectional view of a multilayer substrate in accordance witha preferred embodiment of the present invention;

FIG. 2 is a perspective view of a multilayer substrate in accordancewith a preferred embodiment of the present invention;

FIG. 3 is a sectional view of a multilayer substrate having a circuitpattern in accordance with a preferred embodiment of the presentinvention;

FIG. 4 is an exploded view of a multilayer substrate in accordance witha preferred embodiment of the present invention;

FIG. 5 is an enlarged view of a section of a connector of a multilayersubstrate in accordance with a preferred embodiment of the presentinvention;

FIG. 6 shows the connection between the connector of a multilayersubstrate and the substrate in accordance with a first preferredembodiment of the present invention; and

FIG. 7 shows the connection between the connector of a multilayersubstrate and the substrate in accordance with a second preferredembodiment of the present invention.

KEY DRAWING

FIG. 1

SUMMARY OF THE INVENTION

The present invention discloses a multilayer substrate, which can shieldEMI that can be generated by a high-speed switching element, and amethod for producing it.

The present invention also discloses a multilayer substrate, whichimproves the signal integrity and EMI capacity by sufficiently securinga feedback current path, and a method for producing it.

The present invention also discloses a multilayer substrate, withconstant impedance, by delivering the signal current through a coaxialcable between substrates and a method for producing it.

An aspect of the invention features a multilayer substrate. Themultilayer substrate comprises a first substrate, a connector and asecond substrate. The first substrate has a circuit pattern. Theconnector, coupling onto the first substrate, has a ring structure, inwhich a plurality of holes are separated a predetermined distance fromone another. The second substrate, coupling onto the second substrate byinserting the connector, has a circuit pattern, which is electricallyconnected to a circuit pattern formed on the first substrate using theplurality of holes formed on the connector.

Here, the hole formed on the connector can be a circle, and the insidewall of the plurality of holes formed on the connector can be coatedwith a conductive material.

The multilayer substrate in accordance with the present invention canfurther have a coupling pin, which electrically connects the inside wallof a hole, formed on the connector, to a circuit pattern correspondingto a signal line formed on the first substrate.

The connector can further have a body, a dielectric and a connectingpart. The body is comprised of a conductive material. The dielectriccoats the inside wall of the plurality of holes. The connecting part iscomprised of a conductive material, which coats the dielectric.

A circuit corresponding to the signal line of the first substrate can beelectrically connected to a circuit corresponding to the signal line ofthe second substrate via the connecting part, and the body of theconnector can be connected to a ground and the connecting part of theconnector can be connected to a signal line.

Another aspect of the present invention features a multilayer substratehaving a first substrate, a connector, a first coupling pin, a secondsubstrate and a second coupling pin. The first substrate has a circuitpattern. The connector, coupling onto the first substrate, has a bodyand a connector. The body has a plurality of holes, which are separateda predetermined distance from one another. The body is comprised of aconductive material. The cross section of the connecting part is an “H”shape. The connecting part is comprised of a dielectric and a conductivematerial. The dielectric “coats the inside wall of the plurality ofholes, and the conductive material coats the dielectric. One end of thefirst coupling pin is housed in a slot formed on a connecting part ofthe connector, and the other end is electrically connected to a circuit,which corresponds to a signal line formed on the first substrate. Thesecond substrate, coupling onto the first substrate by inserting theconnector, has a circuit pattern, which is electrically connected to acircuit pattern formed on the first substrate using the plurality ofholes formed on the connector. One end of the second coupling pin ishoused in a slot formed on a connecting part of the connector, and theother end is electrically connected to a circuit, which corresponds to asignal line formed on the second substrate.

Here, the hole formed on the connector can be a circle, and the body ofthe connector can be connected to a ground.

Another aspect of the present invention features a method for producinga multilayer substrate. The method includes stacking a first substrate,on which a circuit pattern is formed. A connector, coupling onto thefirst substrate, is stacked. The connector has a ring structure, inwhich a plurality of holes are separated a predetermined distance fromone another. A second substrate, coupling onto the first substrate byinserting the connector, is stacked. The second substrate has a circuitpattern, which is electrically connected to a circuit pattern, formed onthe first substrate, using the plurality of holes formed on theconnector.

Here, the hole formed on the connector can be a circle, and the insidewall of the plurality of holes formed on the connector can be coatedwith a conductive material.

The method for producing a multilayer substrate in accordance with thepresent invention can further have the step of stacking a coupling pin,which electrically connects the inside wall of a hole, formed on theconnector, to a circuit pattern corresponding to a signal line formed onthe first substrate.

In the method, the connector can further have a body, a dielectric and aconnecting part. The body is comprised of a conductive material. Thedielectric coats the inside wall of the plurality of holes. Theconnecting part is comprised of a conductive material, which coats thedielectric.

A circuit corresponding to the signal line of the first substrate can beelectrically connected to a circuit corresponding to the signal line ofthe second substrate via the connecting part.

The body of the connector can be connected to a ground and theconnecting part of the connector can be connected to a signal line.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, preferred embodiments of the multilayer substrate and themethod for producing it in accordance with the present invention will bedescribed with reference to the accompanying drawings. In referencingthe accompanying drawings, identical elements are assigned the samereference numerals, regardless of their figure numbers, and thedescription for identical elements having the same reference numeralswill not be repeated.

FIG. 1 is a sectional view of a multilayer substrate, in which asingle-side PCB, double-side PCBs and multilayer PCBs are stacked, inaccordance with a preferred embodiment of the present invention, andFIG. 2 is a perspective view of a multilayer substrate illustrated inFIG. 1. Referring to FIGS. 1 and 2, high-speed switching elements 105,135, multilayer PCBs 110, 170, connector bodies 120, 140, 160, 180,dielectric 123, connecting part 125, single-side PCB 130 and double-sidePCBs 150, 190 are illustrated. FIG. 2 shows the cutting line (k)-(k′),on which the sectional view of FIG. 1 is formed.

The high-speed switching element 105, 135, which may be diodes forswitching, insulated gate bipolar transistors (IGBT) and field-effecttransistors (FET), performs a variety of functions, including preventingthe distortion of the on-off-controlled switching voltage waveform byswitching at a high-speed. When a high-speed pulse operates a switchingelement, EMI and REI (radio frequency interference) occur.

The single-side PCB 130 has circuits wired on one side of the insulatedboard; the double-side PCB 150, 190 on both sides; and the multilayerPCB 110, 170 on a multiple of layers. Here, a multilayer substraterefers to a substrate on which the various types of PCBs describedabove, low temperature co-fired ceramic substrates and multi-layerceramic substrates are stacked parallel to one another. Below, themethod for stacking PCBs is described.

The connector 120, 123, 125, 140, 160, 180 comprises the connector body120, 140, 160, 180, dielectric 123 and connecting part 125. Theconnector 120, 123, 125, 140, 160, 180 has a ring-type structure,wherein the shape of the ring depends on the shape of the substrate, towhich the ring is coupled, and may be a rectangle. Moreover, theconnector 120, 123, 125, 140, 160, 180 has a height that issubstantially great enough to prevent the high-speed switching element105, 135, mounted on the lower substrate, from being in contact with theupper substrate, and functions to support each substrate. The connector120, 123, 125, 140, 160, 180 can shield EMI generated by the high-speedswitching element 105, 135. Electromagnetic shielding is a phenomenon ofthe external electromagnetic field not affecting the inside of anelectronic apparatus or the internal electromagnetic field not affectingthe outside of an electronic apparatus when a space is surrounded by anelectrical conductor. Therefore, the connector 120, 123, 125, 140, 160,180 can shield the internal electromagnetic field generated by thehigh-speed switching element 105, 135, mounted on a substrate, or theexternal electromagnetic field.

The connector body 120, 140, 160, 180 surrounds the high-speed switchingelement 105, 135 and can be made from conductive materials, in whichcase it is grounded. The dielectric 123 is coated on the inside wall ofholes formed on the connector, and the connecting part 125 is made fromconductive materials and is coated on the dielectric 123. Here, theholes formed on the connector are arranged with a certain distanceapart, and the shape can vary, from a rectangle to a circle. Thedistance between and the number of holes can be decided in accordancewith the circuit pattern of the upper and lower substrates. In case theholes are shaped circular, a structure similar to a coaxial cable isformed by the dielectric 123 and the connecting part 125. If a coaxialcable is formed by the holes, constant impedance is formed, and acoupling pin that electrically connects signal lines between substratescan be easily fitted. If the connector body 120, 140, 160, 180 is not ofa conductive material, the connecting part 125, which is a conductivematerial formed on each hole, can perform the role of partiallyshielding the electromagnetic field.

Here, various embodiments can be implemented as long as the connectingpart 125 is a structure that can be connected to the signal line of thecircuit on the upper and lower substrates. For example, the connectingpart 125 can be coated on the dielectric 123 and be filled in each holeformed on the connector to be electrically connected to the substratecircuit directly. In another embodiment, the connecting part 125 can becoated on the dielectric 123 and be formed in the middle area of thehole to be electrically connected to the substrate circuit, using acoupling pin having a shape corresponding to the space formed by theconnecting part 125.

FIG. 3 is a sectional view of a multilayer substrate, on which a circuitpattern containing signal lines and a ground line is formed, based on apreferred embodiment of the present invention. Illustrated in FIG. 3 area connector body 120, a dielectric 123, a connecting part 125,high-speed switching elements 127, 310 and signal lines 129.

Stacked on the upper part and the lower part of the connector 120, 123,125 is a single-side multilayer PCB, on which a circuit patterncontaining the signal lines 129 and a ground line is formed. Here, thesignal lines 129 of the upper substrate and the lower substrate areelectrically connected using the connecting part 125 of the connector.By electrically connecting to the ground line, the connector body 120can perform the role of shielding the internal electromagnetic fieldgenerated by the high-speed switching element 127 mounted on thesubstrate or the external electromagnetic field generated by thehigh-speed switching element 310 mounted outside.

FIG. 4 is an exploded perspective view of a multilayer substratecontaining a connector in accordance with a preferred embodiment of thepresent invention, and FIG. 5 is an enlarged view of a section of theconnector indicated by section A in FIG. 4.

Illustrated in FIG. 4 are multilayer PCBs 110, 170, connector bodies120, 140, 160, 180, a single-side PCB 130, a high-speed switchingelement 135, double-side PCBs 150, 190 and a coupling pin 410. Themultilayer PCBs 110, 170, single-side PCB 130 and double-side PCBs 150,190 are separately fabricated, and each of these PCBs is coupled byinserting a connector. The number of PCBs to be coupled and connectorsdepends on the size and features of the system to implement.

The coupling pin 410 connects each of the multilayer PCBs 110, 170,single-side PCB 130 and double-side PCBs 150, 190 and the connectingpart of the connector electrically. The coupling pin 410 has protrudedparts on both ends, and each protruded end is inserted to a hole formedon the PCB and a hole formed on the connector, respectively.Consequently, the coupling pin 410 is connected to the connecting partformed in the hole of the connector electrically, and connects thesignal line formed on each of the PCBs electrically.

So far, a multilayer substrate and a method for producing it have beendescribed with reference to the generally-illustrated sectional viewsand exploded perspective views. Hereinafter, a multilayer substrate anda method for producing it will be described by use of specificembodiments with reference to the accompanying drawings. Described beloware two embodiments, the first of which is a method of using thecoupling pin on one side of the connector to connect to the substrate,and the second of which is using the coupling pin on both sides of theconnector to connect to the substrate.

FIG. 6 illustrates one side of the connector connecting to the substrateusing the coupling pin in accordance with a first preferred embodimentof the present invention. Shown in FIG. 6 are a connector body 610, adielectric 613, a connecting part 615, a coupling pin 620, a couplingpin fixing part 625 and a PCB 630.

The coupling pin 620, which is a conductive material, has at one end aprotruded part that corresponds to the shape of a space formed by theconnecting part 615 of the connector, and at the other end anotherprotruded part that corresponds to the shape of a slot formed on the PCB630. Here, the slot formed on the PCB 630 may be a via hole. In case thecoupling pin 620 couples onto the connecting part 615 of the connectorand the PCB 630, using the protruded parts, the signal line in the PCB630 is electrically connected to the connecting part 615 of theconnector by the coupling pin 620.

The coupling pin fixing part 625 fixes the coupling pin 620 to the PCB630. The coupling pin fixing part 625 may be made from lead, in whichcase the coupling pin fixing part 625 may be molten during the reflowsoldering such that the coupling pin 620 is fixed to the PCB 630.

Here, the connecting part 615 of the connector is extended all the wayto the top of the connector. Thus, the connecting part 615 of theconnector may be directly in contact with the signal circuit of anotherPCB stacked on the top of the connector.

FIG. 7 illustrates the connector of a multilayer substrate connecting tothe substrate in accordance with a second preferred embodiment of thepresent invention. Illustrated in FIG. 7 are a connector body 710, adielectric 713, a connecting part 715, coupling pins 720, 740, couplingpin fixing parts 725, 745, a first PCB 750 and a second PCB 730. Thedescription for the coupling pin 720, 740 and the coupling pin fixingpart 725, 745 is identical to the first embodiment, and only thedifferences will be described below.

The first PCB 750 and the second PCB 730 are coupled by the insertion ofa connector. Here, the connecting part 715 has at both ends slotscorresponding to the protruded parts of the coupling pins 740, 720 suchthat the coupling pins 740, 720, coupled onto the first PCB 750 and thesecond PCB 730, can fit in. The signal circuits on the first PCB 750 andthe second PCB 730 maybe electrically connected with each other throughthe coupling pins 740, 720.

Here, separate coupling pins 740, 720 are inserted in the upper slot andthe lower slot because the cross section of the connecting part 715 hasan “H” shape. If the connecting part 715 is absent or transpierced,however, the signal circuit on the first PCB 750 and the signal circuiton the second PCB 730 may be electrically connected by use of a singlecoupling pin.

As described above, a multilayer substrate and a method for producing itin accordance with the present invention can shield the EMI generated bya high-speed switching element.

Moreover, a multilayer substrate and a method for producing it inaccordance with the present invention can improve the signal integrityand EMI capacity by sufficiently securing a feedback current path.

Furthermore, a multilayer substrate and a method for producing it inaccordance with the present invention can provide constant impedance bydelivering the signal current through a coaxial cable betweensubstrates.

The present invention is by no means restricted by the aforementionedembodiments, and anyone of ordinary skill in the art to which theinvention pertains shall be able to understand that a very large numberof permutations are possible within the scope of the invention.

1. A multilayer substrate comprising: a first substrate, the firstsubstrate having a circuit pattern; a connector, the connector couplingonto said first substrate, the connector having a ring structure, thering structure having a plurality of holes separated a predetermineddistance from one another; and a second substrate, the second substratecoupling onto said first substrate by inserting said connector, thesecond substrate having a circuit pattern, the circuit pattern beingelectrically connected to a circuit pattern formed on said firstsubstrate, the circuit pattern being electrically connected using theplurality of holes formed on said connector.
 2. The multilayer substrateof claim 1, wherein the hole formed on said connector is a circle. 3.The multilayer substrate of claim 1, wherein the inside wall of theplurality of holes formed on said connector is coated with a conductivematerial.
 4. The multilayer substrate of claim 3, further comprising acoupling pin, the coupling pin electrically connecting the inside wallof a hole to a circuit, the hole being formed on said connector, thecircuit corresponding to a signal line formed on said first substrate.5. The multilayer substrate of claim 1, wherein said connector furthercomprises: a body, the body being comprised of a conductive material; adielectric, the dielectric coating the inside wall of said plurality ofholes; and a connecting part, the connecting part being comprised of aconductive material, the conductive material coating said dielectric. 6.The multilayer substrate of claim 5, wherein a circuit corresponding tothe signal line of said first substrate is electrically connected to acircuit corresponding to the signal line of said second substrate viasaid connecting part.
 7. The multilayer substrate of claim 5, whereinthe body of said connector is connected to a ground and the connectingpart of said connector is connected to a signal line.
 8. A multilayersubstrate comprising: a first substrate, the first substrate having acircuit pattern; a connector, the connector coupling onto said firstsubstrate, the connector comprising a body, the body having a ringstructure, the body having a plurality of holes separated apredetermined distance from one another, the body being comprised of aconductive material, the connector comprising a connecting part, theconnecting part having a cross section of an “H” shape, the connectingpart being comprised of a dielectric and a conductive material, thedielectric coating the inside wall of said plurality of holes, theconductive material coating said dielectric; a first coupling pin,wherein one end is housed in a slot formed on a connecting part of saidconnector and the other end is electrically connected to a circuitcorresponding to a signal line formed on said first substrate; a secondsubstrate, the second substrate coupling onto said first substrate byinserting said connector, the second substrate having a circuit pattern,the circuit pattern being electrically connected to a circuit patternformed on said first substrate, the circuit pattern being electricallyconnected using the plurality of holes formed on said connector; and asecond coupling pin, wherein one end is housed in a slot formed on aconnecting part of said connector and the other end is electricallyconnected to a circuit corresponding to a signal line formed on saidsecond substrate;
 9. The multilayer substrate of claim 8, wherein thehole formed on said connector is a circle.
 10. The multilayer substrateof claim 8, wherein the body of said connector is connected to a ground.11. A method for producing a multilayer substrate, the method comprisingthe steps of: stacking a first substrate, the first substrate having acircuit pattern; stacking a connector, the connector coupling onto saidfirst substrate, the connector having a ring structure, the ringstructure having a plurality of holes separated a predetermined distancefrom one another; and stacking a second substrate, the second substratecoupling onto said first substrate by inserting said connector, thesecond substrate having a circuit pattern, the circuit pattern beingelectrically connected to a circuit pattern formed on said firstsubstrate, the circuit pattern being electrically connected using theplurality of holes formed on said connector.
 12. The method of claim 11,wherein the hole formed on said connector is a circle.
 13. The method ofclaim 11, wherein the inside wall of the plurality of holes formed onsaid connector is coated with a conductive material.
 14. The method ofclaim 13, further comprising the step of stacking a coupling pin, thecoupling pin electrically connecting the inside wall of a hole to acircuit, the hole being formed on said connector, the circuitcorresponding to a signal line formed on said first substrate.
 15. Themethod of claim 11, wherein said connector further comprises: a body,the body being a conductive material; a dielectric, the dielectriccoating the inside wall of said plurality of holes; and a connectingpart, the connecting part being comprised of a conductive material, theconductive material coating said dielectric.
 16. The method of claim 15,wherein a circuit corresponding to the signal line of said firstsubstrate is electrically connected to a circuit corresponding to thesignal line of said second substrate via said connecting part.
 17. Themethod of claim 15, wherein the body of said connector is connected to aground and the connecting part of said connector is connected to asignal line.